Single battery, battery pack and power utilization device

Abstract

The invention discloses a single battery, a battery pack and a power utilization device, and belongs to the technical field of batteries, the single battery comprises a shell and a cover plate, an anti-explosion valve covers an anti-explosion hole of the cover plate, the anti-explosion valve comprises a bearing part, a weak part and a protruding part, the bearing part is connected to the weak part in a surrounding manner, the weak part is connected to the protruding part in a surrounding manner, and the bearing part is connected to the cover plate. The weak part is configured to be damaged when impacted by preset pressure, the protruding part protrudes from the connecting position of the weak part to the side away from the electrode assembly, in the thickness direction of the cover plate, the maximum size of the cover plate is A mm, the maximum size of the protruding part is C mm, and C / A is larger than or equal to 0.4 and smaller than or equal to 0.7. The protruding part is arranged to absorb and disperse the stress brought to the anti-explosion valve by the pressure difference between the interior of the containing cavity and the exterior of the shell in the single battery production process, the ratio range of the maximum size C of the protruding part and the maximum size A of the cover plate is limited, the risk that the anti-explosion valve is abnormally cracked and the valve is opened in advance can be reduced, and meanwhile the safety of the anti-explosion valve is improved. And the problem that the protruding part of the anti-explosion valve is crushed and sunken is solved.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a single cell, a battery pack and an electrical device. Background Art

[0002] Lithium-ion batteries are currently widely used in various fields such as transportation power supply, electric energy storage power supply, new energy storage power supply, aerospace and military industry due to their large capacity, high operating voltage, strong charge retention ability and long cycle life. The cover plate in the battery is usually integrated with poles, explosion-proof valves and other structures. Among them, the main function of the explosion-proof valve is to release pressure and exhaust. It is used for the directional release of internal high-temperature and high-pressure gas when the battery cell has thermal runaway due to mechanical impact, internal abnormal lap short circuit and other reasons, thereby improving the safety performance of the battery pack. However, in the processes of battery cell injection, pre-charging formation, and capacity division, there is a repeated positive and negative alternating pressure difference between the inside of the battery and the outside world, which causes deformation, cracking, premature opening of the explosion-proof valve and other problems, seriously affecting the battery process yield and safety performance. Summary of the invention

[0003] Purpose of the invention: The embodiments of the present application provide a single cell, a battery pack and an electrical device, aiming to solve the technical problems of deformation, cracking and premature opening of the explosion-proof valve due to pressure difference during the battery preparation process.

[0004] Technical solution: The present application embodiment provides a single battery, including:

[0005] A housing having a receiving cavity;

[0006] An electrode assembly, the electrode assembly is located in the accommodating cavity;

[0007] A cover plate, which is connected to the shell and covers the accommodating cavity, and is provided with an explosion-proof hole;

[0008] An explosion-proof valve, the explosion-proof valve cover seals the explosion-proof hole, the explosion-proof valve comprises a bearing portion, a weak portion and a protruding portion, the bearing portion is connected to the weak portion in a surrounding manner, the weak portion is connected to the protruding portion in a surrounding manner, the bearing portion is connected to the cover plate, the weak portion is configured to be destroyed when subjected to a preset pressure impact, and the protruding portion protrudes from the connection with the weak portion toward a side away from the electrode assembly;

[0009] Among them, in the thickness direction of the cover plate, the maximum size of the cover plate is A mm, and the maximum size of the protruding portion is C mm, satisfying: 0.4≤C / A≤0.7.

[0010] In some embodiments, the single battery satisfies: 1.5≤A≤2.5, 0.8≤C≤2.0.

[0011] In some embodiments, the single battery satisfies: 1.5≤A≤2, 0.8≤C≤1.5.

[0012] In some embodiments, the single battery satisfies: 2<A≤2.5, 1.0≤C≤2.0.

[0013] In some embodiments, the thickness of the protrusion is t mm, satisfying: 0.15≤t≤0.3.

[0014] In some embodiments, the bearing portion is connected to a side of the cover plate close to the electrode assembly, and the protruding portion protrudes into the explosion-proof hole.

[0015] In some embodiments, a limiting groove is provided on one side of the cover plate close to the electrode assembly. The limiting groove is arranged around the explosion-proof hole and is provided on one side of the cover plate close to the electrode assembly. The bearing portion is arranged in the limiting groove.

[0016] In some embodiments, along the thickness direction, the bearing portion has a maximum dimension B mm, and a minimum dimension D mm is provided between the bottom wall of the limiting groove and a side of the cover plate close to the electrode assembly, satisfying: D≥B, 0.4≤B≤0.6.

[0017] Accordingly, an embodiment of the present application provides a battery pack, comprising the above-mentioned single battery.

[0018] Correspondingly, an embodiment of the present application provides an electrical device, including the above-mentioned single battery, or including the above-mentioned battery pack.

[0019] Beneficial effects: The single cell of the embodiment of the present application includes a shell, an electrode assembly, a cover plate and an explosion-proof valve. The shell has a housing cavity; the electrode assembly is located in the housing cavity; the cover plate is connected to the shell and covers the housing cavity, and the cover plate is provided with an explosion-proof hole; the explosion-proof valve covers the explosion-proof hole, and the explosion-proof valve includes a bearing part, a weak part and a protruding part, the bearing part is connected around the weak part, the weak part is connected around the protruding part, the bearing part is connected to the cover plate, the weak part is configured to be destroyed when subjected to a preset pressure shock, the protruding part protrudes from the connection with the weak part toward the side away from the electrode assembly, in the thickness direction of the cover plate, the maximum size of the cover plate is A mm, the maximum size of the protruding part is C mm, and the following is satisfied: 0.4≤C / A≤0.7. The protruding part is provided to absorb the stress caused to the explosion-proof valve by the pressure difference between the housing cavity and the outside of the shell during the production of the dispersed single cell. In addition, by limiting the ratio range of the maximum dimension C of the protrusion to the maximum dimension A of the cover plate, the risk of abnormal cracking and premature opening of the explosion-proof valve can be reduced while avoiding the problem of the protrusion of the explosion-proof valve being crushed and sunken, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0020] The battery pack of the embodiment of the present application includes the above-mentioned single battery, so the battery pack can have all the technical features and beneficial effects of the above-mentioned single battery, which will not be repeated here.

[0021] The electrical device of the embodiment of the present application includes the above-mentioned single cell or the above-mentioned battery pack, so the electrical device can have all the technical features and beneficial effects of the above-mentioned single cell or battery pack, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 is an exploded diagram of a single cell of an embodiment of the present application;

[0024] Figure 2 is a cross-sectional view of a cover plate according to an embodiment of the present application;

[0025] Figure 3 is a top view of an explosion-proof valve according to an embodiment of the present application;

[0026] Figure 4 is a bottom view of an explosion-proof valve according to an embodiment of the present application;

[0027] Figure 5 It is a cross-sectional view of an explosion-proof valve according to an embodiment of the present application.

[0028] Figure numerals: 1, shell; 2, electrode assembly; 3, cover plate; 4, explosion-proof valve; 10, accommodating chamber; 30, explosion-proof hole; 31, limiting groove; 40, bearing part; 41, weak part; 42, protruding part; 310, bottom wall; 410, notch; X, thickness direction. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0030] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined. In the description of this application, "vertical" means completely vertical at 90° or almost completely vertical, for example, an angle within the range of 80° to 100° is considered vertical. Similarly, "parallel" means completely parallel or almost completely parallel, for example, an angle within 10° of completely parallel is considered parallel.

[0031] The applicant noted that lithium-ion batteries are currently widely used in various fields such as transportation power supply, electric energy storage power supply, new energy storage power supply, aerospace and military industry due to their large capacity, high operating voltage, strong charge retention ability and long cycle life. The cover plate in the battery is usually integrated with poles, explosion-proof valves and other structures. Among them, the main function of the explosion-proof valve is to release pressure and exhaust. It is used for the directional release of internal high-temperature and high-pressure gas when the battery cell has thermal runaway due to mechanical impact, internal abnormal lap short circuit and other reasons, thereby improving the safety performance of the battery pack. However, in the processes of battery cell injection, pre-charging formation, and capacity division, there is a repeated positive and negative alternating pressure difference between the inside of the battery and the outside world, which causes deformation, cracking, premature opening of the explosion-proof valve and other problems, seriously affecting the battery process yield and safety performance.

[0032] In view of this, the embodiment of the present application provides a single cell, a battery pack and an electrical device, including a shell, an electrode assembly, a cover plate and an explosion-proof valve. The shell has a housing cavity; the electrode assembly is located in the housing cavity; the cover plate is connected to the shell and covers the housing cavity, and the cover plate is provided with an explosion-proof hole; the explosion-proof valve covers the explosion-proof hole, and the explosion-proof valve includes a bearing part, a weak part and a protruding part, the bearing part is connected around the weak part, the weak part is connected around the protruding part, the bearing part is connected to the cover plate, the weak part is configured to be destroyed when subjected to a preset pressure shock, and the protruding part protrudes from the connection with the weak part toward a side away from the electrode assembly. In the thickness direction of the cover plate, the maximum size of the cover plate is A mm, and the maximum size of the protruding part is C mm, satisfying: 0.4≤C / A≤0.7. The protruding part is provided to absorb and disperse the stress brought to the explosion-proof valve by the pressure difference between the housing cavity and the outside of the shell during the production of the single cell. In addition, by limiting the ratio range of the maximum dimension C of the protrusion to the maximum dimension A of the cover plate, the risk of abnormal cracking and premature opening of the explosion-proof valve can be reduced while avoiding the problem of the protrusion of the explosion-proof valve being crushed and sunken, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0033] In the present application, the single cell may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, etc., and the embodiments of the present application do not limit this. The single cell may be cylindrical, flat, rectangular or other shapes, and the embodiments of the present application do not limit this. Single cells are generally divided into three types according to the packaging method: cylindrical single cells, square single cells and soft-pack single cells, and the embodiments of the present application do not limit this.

[0034] The following is a detailed description of the single cell, battery pack and electrical device of the present application in conjunction with the accompanying drawings. The features of the following embodiments and implementations can be combined with each other if there is no conflict.

[0035] Figure 1 is an exploded diagram of a single cell of an embodiment of the present application; Figure 2 is a cross-sectional view of a cover plate 3 according to an embodiment of the present application; Figure 3 is a top view of an explosion-proof valve 4 according to an embodiment of the present application; Figure 4 It is a bottom view of an explosion-proof valve 4 according to an embodiment of the present application; Figure 5 It is a cross-sectional view of an explosion-proof valve 4 according to an embodiment of the present application.

[0036] refer to Figures 1 to 5The embodiment of the present application provides a single cell, including a shell 1, an electrode assembly 2, a cover plate 3 and an explosion-proof valve 4. The shell 1 has a housing 10; the electrode assembly 2 is located in the housing 10; the cover plate 3 is connected to the shell 1 and covers the housing 10, the cover plate 3 is provided with an explosion-proof hole 30, the explosion-proof valve 4 covers the explosion-proof hole 30, the explosion-proof valve 4 includes a bearing part 40, a weak part 41 and a protruding part 42, the bearing part 40 is connected to the weak part 41 around, the weak part 41 is connected to the protruding part 42 around, the bearing part 40 is connected to the cover plate 3, and the weak part 41 is configured to be destroyed when subjected to a preset pressure impact. On the one hand, it can ensure the sealing requirements of the single cell in normal use, and on the other hand, it can ensure smooth explosion when subjected to pressure, and facilitate exhaust. When the internal pressure of the single cell is too large (for example, overcharging causes excessive internal pressure), the weak part 41 of the explosion-proof valve 4 is destroyed by the preset pressure to release the internal gas of the single cell, thereby reducing the internal pressure of the single cell, and preventing the internal pressure of the single cell from being too quickly pressurized, causing the single cell to explode, etc. The protrusion 42 protrudes from the connection with the weak portion 41 toward the side away from the electrode assembly 2. The setting of the protrusion 42 can avoid stress concentration. The protrusion 42 can absorb and disperse the stress caused by the pressure difference between the accommodating cavity 10 and the outside of the shell 1 to the explosion-proof valve 4 during the production of the single battery, and avoid the deformation of the weak portion 41 due to the pressure difference, which leads to the cracking of the weak portion 41 or the premature opening of the explosion-proof valve 4. Among them, in the thickness direction X of the cover plate 3, the maximum size of the cover plate 3 is A mm, and the maximum size of the protrusion 42 is C mm, which satisfies: 0.4≤C / A≤0.7.

[0037] It is understandable that if the ratio of the maximum dimension C of the protrusion 42 to the maximum dimension A of the cover plate is too small, in the processes of liquid injection, pre-charging formation, and capacity division in the single cell manufacturing process, when there is a positive and negative alternating pressure difference between the single cell accommodating cavity and the outside world, the weak portion 41 is prone to deformation and cracking, or the explosion-proof valve 4 opens prematurely. If the ratio of the maximum dimension C of the protrusion 42 to the maximum dimension A of the cover plate is too large, the protrusion 42 is easily crushed and sunken, affecting the normal function of the explosion-proof valve 4. The embodiment of the present application limits the range of the ratio of the maximum dimension C of the protrusion 42 to the maximum dimension A of the cover plate, while reducing the risk of abnormal cracking and premature opening of the explosion-proof valve 4, it can avoid the problem of the protrusion 42 of the explosion-proof valve 4 being crushed and sunken, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0038] exist Figure 5In the illustrated embodiment, the thickness of the protrusion 42 is t mm, satisfying: 0.15≤t≤0.3. Exemplarily, the thickness t of the protrusion 42 can be any value among 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, or a range of values ​​between any two of them. If the thickness t of the protrusion 42 is too small, the structural strength of the explosion-proof valve 4 may be reduced, and the stress caused by the internal and external pressure difference in the single cell manufacturing process may not be fully dispersed and absorbed, increasing the risk of abnormal cracking and premature opening of the explosion-proof valve 4. If the thickness t of the protrusion 42 is too large, the overall weight of the explosion-proof valve 4 may increase, which may cause the explosion-proof valve 4 to respond more slowly when the pressure changes, and fail to open the valve in time, increasing the risk of fire and explosion of the single cell. By limiting the thickness t of the protruding portion, the structural strength of the explosion-proof valve 4 can be ensured, and abnormal cracking and premature opening of the explosion-proof valve 4 can be avoided. At the same time, the performance of the explosion-proof valve 4 can be ensured so that the valve can be opened normally at a preset pressure in the accommodating chamber 10, thereby improving the safety and reliability of the single battery.

[0039] In some embodiments, in the thickness direction X of the cover plate 3, the bearing portion 40 has a maximum dimension B mm, satisfying: 0.4≤B≤0.6. Exemplarily, the maximum dimension B of the bearing portion 40 can be any one of 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, 0.6, or a range of values ​​between any two of them. Such a setting can ensure the connection stability between the bearing portion 40 and the cover plate 3, avoid the loosening or falling off of the explosion-proof valve 4 due to unstable connection during the single cell manufacturing process or normal use, and improve the safety and reliability of the single cell.

[0040] In some embodiments, the single cell satisfies: 1.5≤A≤2.5, 0.8≤C≤2.0. Exemplarily, the maximum size A of the cover plate can be any one of 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, or a range of values ​​between any two. In this way, it can be ensured that the cover plate 3 has sufficient strength to effectively cover the accommodating cavity 10 and ensure the structural stability of the single cell. The maximum size C of the protrusion 42 can be any one of 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or a range of values ​​between any two. In this way, while reducing the risk of abnormal cracking and premature opening of the explosion-proof valve 4, the protrusion 42 of the explosion-proof valve 4 can be avoided from being crushed and sunken, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0041] In some embodiments, the single cell satisfies: 1.5≤A≤2, 0.8≤C≤1.5. In the embodiments of the present application, the maximum dimension B of the load-bearing portion 40 in the thickness direction X is designed to be 0.5, the maximum dimension A of the cover plate 3 in the thickness direction X is between 1.5 and 2, and explosion-proof valves 4 of different sizes C are provided and welded to the cover plate 3. By tracking and testing the thickness of the notch of the explosion-proof valve 4 and the application process of the production line cover plate 3, the influence of the ratio of C / A on the residual thickness of the notch of the explosion-proof valve 4 and the application of the production line is verified under the same bursting pressure. The verification effect is shown in Table 1.

[0042] Table 1:

[0043]

[0044] Referring to Examples 1 to 7 in Table 1, when the maximum dimension C of the protrusion 42 and the maximum dimension A of the cover plate simultaneously satisfy 1.5≤A≤2, 0.8≤C≤1.5, and 0.4≤C / A≤0.7, the average bursting pressure is 0.9 MPa, and the residual thickness of the notch 410 of the explosion-proof valve 4 is basically stable between 68.5μm and 69.8μm. The structural strength of the explosion-proof valve 4 is improved, which can reduce the risk of abnormal cracking and premature opening of the explosion-proof valve 4, and the problem of the protrusion 42 of the explosion-proof valve 4 being crushed and depressed does not occur.

[0045] Referring to Comparative Examples 1 to 3 in Table 1, when the ratio of C / A is less than 0.4, that is, when the maximum dimension C of the protrusion 42 is too small, the residual thickness of the notch 410 of the explosion-proof valve 4 is between 60.1 μm and 64.4 μm. It is understandable that the small size of the protrusion 42 may result in the failure to fully absorb and disperse the stress caused by the pressure difference between the accommodating cavity 10 and the outside of the shell 1 to the explosion-proof valve 4 during the production of the single battery, thereby causing the weak portion 41 to deform due to the pressure difference, and it is easy to cause the weak portion 41 to deform, crack, or the explosion-proof valve 4 to open prematurely.

[0046] Referring to Comparative Examples 4 and 5 in Table 1, when the ratio of C / A is greater than 0.7, that is, when the maximum dimension C of the protrusion 42 is too large, the residual thickness of the notch 410 of the explosion-proof valve 4 does not change much. However, the problem of the protrusion 42 of the explosion-proof valve 4 being crushed and sunken occurs in the single cell process, affecting the single cell process yield and safety performance.

[0047] In some embodiments, the single cell satisfies: 2<A≤2.5, 1.0≤C≤2.0. In the embodiments of the present application, by designing the maximum dimension B of the bearing portion 40 in the thickness direction X to be 0.5, the maximum dimension A of the cover plate 3 in the thickness direction X to be between 2 and 2.5, explosion-proof valves 4 of different sizes C are set and welded to the cover plate 3, and by tracking and testing the thickness of the notch of the explosion-proof valve 4 and the application process of the production line cover plate 3, the influence of the ratio of C / A on the residual thickness of the notch of the explosion-proof valve 4 and the application of the production line is verified under the same bursting pressure. The verification effect is shown in Table 2.

[0048] Table 2:

[0049]

[0050]

[0051] Referring to Examples 8 to 13 in Table 2, when the maximum dimension C of the protrusion 42 and the maximum dimension A of the cover plate simultaneously satisfy 2<A≤2.5, 0.8≤C≤2 and 0.4≤C / A≤0.7, the average bursting pressure is 0.9 MPa, and the residual thickness of the notch 410 of the explosion-proof valve 4 is basically stable between 68.8μm and 70.5μm. The structural strength of the explosion-proof valve 4 is improved, which can reduce the risk of abnormal cracking and premature opening of the explosion-proof valve 4, and the problem of the protrusion 42 of the explosion-proof valve 4 being crushed and depressed does not occur.

[0052] Referring to Comparative Examples 6 and 7 in Table 2, when C / A is less than 0.4, that is, when the maximum dimension C of the protrusion 42 is relatively small, the residual thickness of the notch 410 of the explosion-proof valve 4 is 63.3 μm and 65.8 μm respectively. It is understandable that the relatively small protrusion size of the protrusion 42 may result in the failure to fully absorb and disperse the stress caused to the explosion-proof valve 4 by the pressure difference between the accommodating cavity 10 and the outside of the shell 1 during the production of the single battery, thereby causing the weak portion 41 to deform due to the pressure difference, and the weak portion 41 is prone to deformation, cracking, or premature opening of the explosion-proof valve 4.

[0053] Referring to Comparative Examples 8 and 9 in Table 2, when C / A is greater than 0.7, that is, when the maximum dimension C of the protrusion 42 is too large, as the maximum dimension C of the protrusion 42 increases, the residual thickness of the notch 410 of the explosion-proof valve 4 does not change much. However, the problem of the protrusion 42 of the explosion-proof valve 4 being crushed and sunken occurs in the single cell process, affecting the single cell process yield and safety performance.

[0054] In some embodiments, the area of ​​the protrusion 42 is S1 mm 2 , the area of ​​explosion-proof valve 4 is S2 mm 2, satisfying: 0.8≤S1 / S2≤0.85. When the ratio of the area S1 of the protrusion 42 to the area S2 of the explosion-proof valve 4 is too large, it can be understood that the area occupied by the protrusion 42 in the explosion-proof valve 4 is too large, thereby occupying the space of the weak part 41. This may cause the weak part 41 to fail to be destroyed normally when subjected to a preset pressure, affecting the function of the explosion-proof valve 4 to release the internal gas. When the ratio of the area S1 of the protrusion 42 to the area S2 of the explosion-proof valve 4 is too small, the area of ​​the protrusion 42 is too small, and it is impossible to fully absorb and disperse the pressure difference stress from the production process of the single battery, which is easy to cause the weak part 41 to crack due to stress concentration or cause the explosion-proof valve 4 to open the valve in advance, reducing the safety and reliability of the single battery. By limiting the ratio range of the area S1 of the protrusion 42 to the area S2 of the explosion-proof valve 4, the area of ​​the protrusion 42 and the area of ​​the explosion-proof valve 4 are controlled within a certain ratio range, which can ensure that the protrusion 42 reaches a relatively ideal state when playing the role of absorbing and dispersing stress. The protrusion 42 will not be too small to effectively disperse stress, nor will it be too large to affect the pressure relief function of the explosion-proof valve 4. A reasonable area ratio helps the explosion-proof valve 4 to quickly release internal gas when the internal pressure of the single battery is too high, reduce the internal pressure, and improve the safety and reliability of the single battery.

[0055] In some embodiments, a notch 410 is provided at the weak portion 41, and the notch 410 is provided around the protrusion 42. By providing the notch 410, the weak portion 41 can be more accurately ruptured at the notch 410 when subjected to a preset pressure, ensuring that the explosion-proof valve 4 releases the internal gas of the single cell in time under a suitable pressure, thereby effectively reducing the internal pressure and preventing the single cell from being in danger. By forming an annular notch 410 by recessing at least a portion of the weak portion, the local thinning of the annular notch 410 can form a path guide for the opening of the weak portion 41, facilitating the explosion-proof valve to open along the path of the notch 410.

[0056] In some embodiments, the notch 410 may be disposed on a side of the weak portion 41 away from the electrode assembly 2 and recessed toward the electrode assembly 2. In other embodiments, the notch 410 may be disposed on a side of the weak portion 41 close to the electrode assembly 2 and recessed away from the electrode assembly 2. Figure 3 and Figure 5 In the illustrated embodiment, the notch 410 is disposed on a side of the weak portion 41 away from the electrode assembly 2 and is recessed toward the electrode assembly 2. The notch 410 may be formed by laser etching or by mechanical processing, and the present application does not limit this.

[0057] exist Figure 2 and Figure 5In the illustrated embodiment, the bearing portion 40 is connected to the side of the cover plate 3 close to the electrode assembly 2, and the protruding portion 42 protrudes into the explosion-proof hole 30. The explosion-proof valve 4 is arranged on the side of the cover plate 3 close to the electrode assembly 2, which can avoid the problem of the explosion-proof valve 4 being easily damaged by scratches when welding the explosion-proof valve 4 on the outer wall of the cover plate 3, and ensure the connection stability between the explosion-proof valve 4 and the cover plate 3.

[0058] exist Figure 2 and Figure 5 In the illustrated embodiment, a limiting groove 31 is provided on one side of the cover plate 3 close to the electrode assembly 2. The limiting groove 31 is arranged around the explosion-proof hole 30 and is arranged on one side of the cover plate 3 close to the electrode assembly 2. The bearing portion 40 is arranged in the limiting groove 31. The limiting groove 31 can play a role in positioning and fixing the explosion-proof valve 4. By providing the limiting groove 31 on the cover plate 3 and arranging the explosion-proof valve 4 in the limiting groove 31, the explosion-proof valve 4 will not occupy the space of the electrode assembly 2 in the accommodating cavity 10, thereby improving the energy density and performance of the single battery.

[0059] exist Figure 5 In the illustrated embodiment, along the thickness direction X of the cover plate 3, the bearing portion 40 has a maximum dimension Bmm, and the bottom wall 310 of the limiting groove 31 and the side of the cover plate 3 close to the electrode assembly 2 have a minimum dimension Dmm, satisfying: D≥B, 0.4≤B≤0.6. Exemplarily, the maximum dimension B of the bearing portion 40 can be any one of 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, 0.6 or a range value between any two of them. It can be understood that by limiting the minimum dimension D between the bottom wall 310 of the limiting groove 31 and the side of the cover plate 3 close to the electrode assembly 2 to be greater than or equal to the maximum dimension B of the bearing portion 40, the explosion-proof valve 4 can be prevented from protruding from the lower surface of the cover plate 3, thereby preventing the explosion-proof valve 4 from occupying the space of the electrode assembly 2 in the accommodating cavity 10, thereby improving the energy density and performance of the single battery. Furthermore, it is also possible to prevent the explosion-proof valve 4 from colliding or scratching with other components under vibration conditions, thereby reducing the possibility of danger to the single battery due to damage to the explosion-proof valve 4.

[0060] The present application embodiment provides a battery pack, including the above-mentioned single battery, so the battery pack can have all the technical features and beneficial effects of the above-mentioned single battery, which will not be repeated here. The battery pack also includes a box body, wherein at least one single battery is accommodated inside the box body.

[0061] Correspondingly, the embodiment of the present application also provides an electrical device, including the above-mentioned single cell, or, including the above-mentioned battery pack, so the electrical device can have all the technical features and beneficial effects of the above-mentioned single cell or battery pack, which will not be repeated here. The electrical device can be a mobile phone, a portable device, a laptop computer, an electric car, an electric car, a ship, a spacecraft, an electric toy, and an electric tool. For example, spacecraft include airplanes, rockets, space shuttles, and spacecrafts; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0062] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0063] The above is a detailed introduction to a single cell battery, a battery pack and an electrical device provided in the embodiments of the present application, and specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A single cell battery, characterized in that: include: A housing having a receiving cavity; an electrode assembly, wherein the electrode assembly is located in the accommodating cavity; A cover plate, the cover plate is connected to the shell and covers the accommodating cavity, and the cover plate has an explosion-proof hole; an explosion-proof valve, the explosion-proof valve covers the explosion-proof hole, the explosion-proof valve comprises a bearing portion, a weak portion and a protruding portion, the bearing portion is connected around the weak portion, the weak portion is connected around the protruding portion, the bearing portion is connected to the cover plate, the weak portion is configured to be destroyed when impacted by a preset pressure, and the protruding portion protrudes from the connection with the weak portion toward a side away from the electrode assembly; Wherein, in the thickness direction of the cover plate, the maximum dimension of the cover plate is A mm, the maximum dimension of the protrusion is C mm, and the following conditions are satisfied: 0.4≤C / A≤0.

7.

2. The single cell according to claim 1, characterized in that: The single battery satisfies: 1.5≤A≤2.5, 0.8≤C≤2.

0.

3. The single cell according to claim 2, characterized in that: The single battery satisfies: 1.5≤A≤2, 0.8≤C≤1.

5.

4. The single cell according to claim 2, characterized in that: The single battery satisfies: 2.0<A≤2.5, 1.0≤C≤2.

0.

5. The single cell according to claim 1, characterized in that: The thickness of the protrusion is t mm, satisfying: 0.15≤t≤0.3 。 6. The single cell according to claim 1, characterized in that: The bearing portion is connected to a side of the cover plate close to the electrode assembly, and the protruding portion protrudes into the explosion-proof hole.

7. The single cell according to claim 1 or 6, characterized in that: A limiting groove is provided on one side of the cover plate close to the electrode assembly. The limiting groove is arranged around the explosion-proof hole and is provided on one side of the cover plate close to the electrode assembly. The bearing portion is arranged in the limiting groove.

8. The single cell according to claim 7, characterized in that: Along the thickness direction, the bearing portion has a maximum dimension B mm, and a minimum dimension D mm is present between the bottom wall of the limiting groove and a side of the cover plate close to the electrode assembly, satisfying: D ≥ B, 0.4 ≤ B ≤ 0.

6.

9. A battery pack, characterized in that: The invention comprises the single cell according to any one of claims 1 to 8.

10. An electrical device, characterized in that: The method comprises the single cell according to any one of claims 1 to 8, or comprises the battery pack according to claim 9.

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